Percolating Cluster Devices: Possible Neuromorphic Applications

Nanoparticles by Design Unit (Sowwan Unit) would like to announce a seminar by Prof. Simon Brown

Speaker: Prof. Simon Brown, The MacDiarmid Institute for Advanced Materials and Nanotechnology, Dept. of Physics   and Astronomy, University of Canterbury, 8140, Christchurch, New Zealand

Title: Percolating Cluster Devices: Possible Neuromorphic Applications

Abstract:

When clusters (nanoparticles) are randomly deposited on a surface they produce percolating films which have remarkable electrical properties. [1] Here we will focus on devices that contain percolating films of Sn clusters, and especially those that are deliberately constructed so as to guarantee that the film is close to the percolation threshold (onset of conduction). In these devices quantum mechanical tunnelling is important [2], and several new and unexpected phenomena are observed. In particular we have recently demonstrated switching between well-defined, quantized, conductance values [multiples of the quantum of conductance (2e²/h)], at room temperature. [3]

More recently we have developed methods for stabilizing the devices so that they consistently operate for periods of months. [4] Application of controlled pulsed voltage sequences allows us to explore the neuromorphic (i.e. brain-like) properties of the devices. We show that groups of connected clusters can be viewed as analogous to neurons, and that the tunnel gaps provide switching elements analogous to synapses. [5] While this work is still at an early stage the inherent complexity of the networks, which, like the brain are poised near criticality, is promising for on-chip neuromorphic computation. [6]

[1]   J. Schmelzer jr, S. A. Brown, A. Wurl, M. Hyslop, and R. J. Blaikie, Phys. Rev. Lett. 88, 226802 (2002).

[2]   S. Fostner, R. Brown, J. Carr, and S. A. Brown, Phys. Rev. B 89, 075402 (2014).

[3]   A. Sattar, S. Fostner, and S. A. Brown, Phys. Rev. Lett. 111, 136808 (2013).

[4]   S. K. Bose, J. B. Mallinson, R. M. Gazoni and S. A. Brown, Submitted to Appl. Phys. Lett. (2016); International Patent Application Number PCT/NZ2016/050108.

[5]   S. Fostner and S. A. Brown, Phys. Rev. E 92, 052134 (2015).

[6]   R. Service, Science 345, 614 (2014); P. A. Merolla et al, Science 345, 668 (2014).

Host: Mukhles Sowwan, Sowwan Unit

We look forward to seeing many of you.

Sincerely,

Yumi Takahashi

Nanoparticles by Design Unit (Sowwan Unit)